This invention relates to personal containment systems such as protective suits and protective tents adapted to isolate a wearer or user from a contaminated environment. This invention also relates to personal containment systems having a filtered air delivery system.
Personal containment systems can protect a user from a variety of harmful chemical or biological agents. Many examples of personal containment systems that can surround a user are known, such as protective suits, protective tents, casualty bags for injured persons, and the like. These systems preferably isolate the user""s entire body from contaminants. Often, the contaminants include respiratory hazards, and the systems must employ air delivery systems so that the user is able to breathe when isolated from the environment. Respirators are often used in conjunction with personal protection systems to provide the user with purified air. A variety of respirators are known and described below.
Certain personal containment systems employ a non-powered purifying respirator. Air is drawn into the system through a filter by the user""s breathing action. When the user draws a breath, negative pressure is created in the system and air is drawn in through the filter. When the user expels a breath, spent air leaves the system through a valve.
A powered air-purifying respirator (PAPR) can be employed to supply a continuous stream of filtered air under positive pressure to a personal containment system. A typical PAPR includes a filter attached to a blower which delivers filtered air to the system. Such air delivery can involve a conduit that ducts air to a hood or a spigot on a protective garment. PAPRs are generally powered by a battery. When used with a protective garment, the PAPR blower typically is mounted on a belt wrapped around a user""s waist or on a harness strapped to the user""s torso, and worn externally. PAPRs are generally employed in industrial applications where the environmental hazards are well defined and quantified.
A self-contained breathing apparatus (SCBA) is another variety of respirator employed as a part of a personal containment system. A SCBA typically supplies air or oxygen from a portable source to a regulator or other breathing device worn by the user. A SCBA worn inside a sealed protective suit provides the user with a fully contained protective environment. SCBA systems employed in this manner can be used when the nature of the hazard is not known, or in environments that might be void of oxygen.
Recently published PCT Application No. WO 01/74449 A1 describes a protective suit having a harness-borne pump unit positioned inside the suit. A port is provided for air to be drawn in from outside the protective suit. A filter may be positioned outside the suit and screwed to a spigot extending from the pump unit through the port. An air-tight connection is said to be made around the port when the filter and pump are properly connected so that no air may pass through the port without passing through the filter.
If the filter in such a device is misconnected or disconnected, leakage could occur between the port and spigot. In addition, sudden movement by the user or other disturbance of the suit while the filter is disconnected might cause the spigot to withdraw from the port and dangle inside the suit. That could make it much more difficult to replace the filter quickly, especially if filter replacement is attempted while in a hazardous environment.
The invention provides, in one aspect, a personal containment system comprising:
a generally fluid-tight barrier having an inner surface defining an inner environment that can surround a user of the containment system and an outer surface defining an outer environment that can contain one or more hazards;
an air delivery system that can provide filtered air from the outer environment to the inner environment, comprising a replaceable filter exposed to the outer environment and a blower generally isolated from the outer environment and in fluid communication with the filter; and
a port for delivery of filtered air through the barrier to the blower, the port providing a generally fluid tight connection to the barrier and blower during filter replacement.
The invention may permit replacement of the filter under hazardous conditions, without requiring the user to exit a contaminated or otherwise hazardous environment. Leakage of contaminants into the system is minimized, and limited to materials that might enter the blower inlet. The blower inlet remains accessible during filter replacement, thereby speeding and simplifying the filter replacement process.